The last emperor of China lived out a decade as a civilian under Chinese Communist rule. It is very possible that the Romanov children could have enjoyed the same fate. Either way, it isn't as though the western powers were shy about funneling money and weapons to the White Army during the 1920s or the German Nationalists during the 1930s or various anti-Communist European factions indefinitely.

Hell, Americans were chomping at the bit to embrace a legion of Anastasia imposters well into the 1990s when FOX Animation Studio decided to climb aboard the revisionist train and plant its own knife in the back of the USSR.

Killing the Romanov kids did exactly dick-all to help the Soviet movement.